Safety and anti-tumor activity of sorafenib (Nexavar®) in combination with other anti-cancer agents: a review of clinical trials

Synthesis, enzyme inhibition assay, and molecular modeling study of novel pyrazolines linked to 4-methylsulfonylphenyl scaffold: antitumor activity and cell cycle analysis

Antitumor activity using 59 cancer cell lines and enzyme inhibitory activity of a newly synthesized pyrazoline-linked 4-methylsulfonylphenyl scaffold (compounds 18a-q) were measured and compared with those of standard drugs. Pyrazolines 18b, 18c, 18f, 18g, 18h, and 18n possessed significant antitumor activity, with a positive cytotoxic effect (PCE) of 22/59, 21/59, 21/59, 48/59, 51/59, and 20/59, respectively. The cancer cell lines HL60, MCF-7, and MDA-MB-231 were used to measure the IC50 values of derivatives 18c, 18g, and 18hvia the MTT assay method, and the results were compared with those of reference drugs. Derivatives 18g and 18h showed potent and broad-spectrum antitumor activities against HL60 (IC50 of 10.43, 8.99 μM, respectively), MCF-7 (IC50 of 11.7 and 12.4 μM, respectively), and MDA-MB-231 (IC50 of 4.07 and 7.18 μM, respectively). Compound 18c exhibited strong antitumor activity against HL60 and MDA-MB-231 cell lines with IC50 values of 8.43 and 12.54 μM, respectively, and moderate antitumor activity against MCF-7 cell lines with an IC50 value of 16.20 μM. Compounds 18c, 18g, and 18h remarkably inhibited VEGFR2 kinase (IC50 = 0.218, 0.168, and 0.135 μM, respectively) compared with the reference drug sorafenib (IC50 = 0.041 μM). Compounds 18g and 18h effectively inhibited HER2 kinase (IC50 = 0.496 and 0.253 μM, respectively) compared with erlotinib (IC50 = 0.085 μM). Compound 18h inhibited EGFR kinase (IC50 = 0.574 μM) with a potency comparable with that of the reference drug erlotinib (IC50 = 0.105 μM). Pyrazolines 18c, 18f, and 18h arrested the S/G2 phase of the cell cycle in HL-60 cells. In addition, derivatives 18c, 18f, and 18h revealed lower Bcl-2 protein expression anti-apoptotic levels and higher Bax, caspase-3, and caspase-9 expression levels. Molecular docking studies of derivative 18h into the binding sites of EGFR, HER2, and VEGFR2 kinases explored the interaction mode of these pyrazoline derivatives and their structural requirements for antitumor activity.

pH-Responsive Sorafenib/Iron-Co-Loaded Mesoporous Polydopamine Nanoparticles for Synergistic Ferroptosis and Photothermal Therapy

Ferroptosis has attracted significant attention as a new mechanism of cell death. Sorafenib (SRF) is widely considered a prototypical ferroptosis-inducing drug, particularly for liver cancer treatment. However, the low solubility and hydrophobic nature of SRF, along with the absence of synergistic therapeutic strategies, still limit its application in cancer treatment. Herein, we report a dual therapeutic method incorporating photothermal therapy and ferroptosis by using Fe-doped mesoporous polydopamine nanoparticles (Fe-mPDA@SRF-TPP) as a carrier for loading SRF and targeting triphenylphosphine (TPP). SRF molecules are efficiently encapsulated within the polydopamine nanospheres with a high loading ratio (80%) attributed to the porosity of Fe-mPDA, and the inherent biocompatibility and hydrophilicity of Fe-mPDA@SRF-TPP facilitate the transport of SRF to the target cancer cells. Under the external stimuli of acidic environment (pH 5.0), glutathione (GSH), and laser irradiation, Fe-mPDA@SRF-TPP shows sustained release of SRF and Fe ions with the ratio of 72 and 50% within 48 h. Fe-mPDA@SRF-TPP nanoparticles induce intracellular GSH depletion, inhibit glutathione peroxidase 4 (GPX4) activity, and generate hydroxyl radicals, all of which are essential components of the therapeutic ferroptosis process for killing MDA-MB-231 cancer cells. Additionally, the excellent near-infrared (NIR) light absorption of Fe-mPDA@SRF-TPP nanoparticles demonstrates their capability for photothermal therapy and further enhances the therapeutic efficiency. Therefore, this nanosystem provides a multifunctional therapeutic platform that overcomes the therapeutic limitations associated with standalone ferroptosis and enhances the therapeutic efficacy of SRF for breast cancer.

Synthesis, molecular docking analysis and in vitro evaluation of new heterocyclic hybrids of 4-aza-podophyllotoxin as potent cytotoxic agents

Two different synthetic approaches to novel heterocyclic hybrid compounds of 4-azapodophyllotoxin were investigated. The obtained products were characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, and high-resolution mass spectrometry. MTT protocol was then performed to examine the cytotoxic activity of these products against KB, HepG2, A549, MCF7, and Hek-293 cell lines. The cytotoxic assessment indicated that all products displayed moderate to high cytotoxicity against all tested cancer cell lines. The most active compound 13k containing the 2-methoxypyridin-4-yl group exhibited selective cytotoxicity against KB, A549, and HepG2 cell lines with the IC50 values ranging from 0.23 to 0.27 μM, which were between 5- to 10-fold more potent than the positive control ellipticine. Compounds 13a (HetAr = thiophen-3-yl) and 13d (HetAr = 5-bromofuran-2-yl) displayed high cytotoxic selectivity for A549 and HepG2 cancer cell lines when compared to the other cancer cell lines and low toxicity to the normal Hek-293 cell line. Molecular docking study was conducted to evaluate the interaction of new synthesized compounds with the colchicine-binding-site of tubulin. Besides that, physicochemical and pharmacokinetic properties of the most active compounds 13h,k were predicted.

Inhibition of Dickkopf-1 enhances the anti-tumor efficacy of sorafenib via inhibition of the PI3K/Akt and Wnt/β-catenin pathways in hepatocellular carcinoma

BACKGROUND

Sorafenib improves the overall survival in patients with advanced hepatocellular carcinoma (HCC). Dickkopf-1 (DKK1) is commonly overexpressed in HCC. In this study, we investigated whether the inhibition of DKK1 enhances the anti-tumor efficacy of sorafenib in HCC.

METHODS

HCC cells were treated with sorafenib and WAY-262611, which is an inhibitor of DKK1. Transgenic mouse models were also developed using hydrodynamic tail vein injection. Mice were orally administered with sorafenib (32 mg/kg), WAY-262611 (16 mg/kg), or sorafenib + WAY-262611 for 10 days. Mechanisms of sorafenib and WAY-262611 were explored via western blotting, immunostaining, and RNA sequencing.

RESULTS

DKK1 was significantly overexpressed in patients with HCC than in the healthy controls and patients with liver diseases except HCC (all P < 0.05). Compared with sorafenib alone, sorafenib + WAY-262611 significantly inhibited the cell viability, invasion, migration, and colony formation by promoting apoptosis and altering the cell cycles in HCC cells (all P < 0.05). Moreover, sorafenib + WAY-262611 decreased the p110α, phospho-Akt (all P < 0.05), active β-catenin (all P < 0.05) and phospho-GSK-3β (Ser9) expression levels, while increasing the phospho-GSK-3β (Tyr216) expression levels compared with those in the sorafenib alone in vitro and in vivo. In addition, sorafenib + WAY-262611 inhibited tumor progression by regulating cell proliferation and apoptosis, significantly better than sorafenib alone in mouse models.

CONCLUSIONS

Our results indicate that DKK1 inhibition significantly enhances the anti-tumor efficacy of sorafenib by inhibiting the PI3K/Akt and Wnt/β-catenin pathways via regulation of GSK3β activity, suggesting a novel therapeutic strategy for HCC. Video Abstract.

Synthesis of novel spirochromane incorporating Schiff's bases, potential antiproliferative activity, and dual EGFR/HER2 inhibition: Cell cycle analysis and in silico study

Spirochromanes incorporating Schiff's bases and semicarbazones 4a-e and 5a-j were synthesizedand analyzed for their potential antiproliferative activity using four human cancer cell lines (MCF-7, HCT-116, PC3, and A549). Compounds 5a, 5b and 5g possessed the highest antiproliferative activity among the tested compounds,with an IC50 range of 1.154-9.09 μM. Compound 5j selectively inhibited the PC3 cell proliferation (IC50 = 5.47 μM). Spirochromanes 5a, 5b and 5g exhibited high inhibitory activity against EGFR (IC50 = 0.116, 0.132, and 0.077 μM, respectively) and HER2 (IC50 = 0.055, 0.210 and 0.085 μM, respectively) compared with the references, erlotinib (IC50 = 0.090 and 0.038 μM, respectively) and gefitinib (IC50 = 0.052 and 0.072 μM, respectively). Cell cycle analysis and apoptosis results showed that compounds 5a, 5b and 5g arrested growth inthe S phase, and the programmed cell death induced by these compounds was an apoptotic mechanism rather than a necrotic pathway. Molecular docking studies of spirochromanes 5a, 5b and 5g to EGFR and HER2 binding sites were performed to explore the orientation mode and interaction.

Cucurbitacin E shows synergistic effect with sorafenib by inducing apoptosis in hepatocellular carcinoma cells and regulates Jak/Stat3, ERK/MAPK, PI3K/Akt/mTOR signaling pathways

OBJECTIVE

Cucurbitacin E (CuE), a natural compound found in medicinal plants such as Ecballium Elaterium, has demonstrated antiproliferative and apoptotic effects in various cancer cell types due to its tetracyclic triterpenoid structure. Sorafenib, a multi-tyrosine kinase inhibitor, is commonly used in hepatocellular carcinoma (HCC) treatment. This study aimed to investigate the anticancer effect of CuE alone and in combination with sorafenib on HepG2 cells.

METHODS

CuE was extracted from Ecballium Elaterium fruit juice and quantitatively evaluated using HPLC. The effect of sorafenib and CuE on cell growth inhibition was determined using the MTT test. Cell cycle progression and apoptosis were assessed using flow cytometry. Mitochondrial damage was evaluated with ΔΨm, and DNA damage was assessed using the comet assay. The expression of Jak2/Stat3, PI3K/Akt/mTOR, MAPK, and Bcl-2 family-related genes and proteins were analyzed using western blot and qRT-PCR, respectively.

RESULTS

Both CuE (0.1-5 µM) and sorafenib (0.5-10 µM) exhibited dose- and time-dependent antiproliferative and cytotoxic effects against the HepG2 cell line. Both compounds induced apoptosis in HepG2 cells and halted the cell cycle in the G2/M phase while causing mitochondrial and DNA damage. Both compounds down-regulated Jak2/Stat3, PI3K/Akt/mTOR, MAPK signaling pathway proteins, and Bcl-xL levels, while up-regulated Caspase-9 and Bax protein levels.

CONCLUSION

Based on the results of this study, it can be concluded that CuE alone or in combination with sorafenib has the potential to be an effective therapeutic option for the treatment of HCC by inducing apoptosis and regulating multiple signaling pathways.

Nanoplatforms: The future of oral cancer treatment

Background and Aims

Cytotoxicity is a key disadvantage of using chemotherapeutic drugs to treat cancer. This can be overcome by encapsulating chemotherapeutic drugs in suitable carriers for targeted delivery, allowing them to be released only at the cancerous sites. Herein, we aim to review the recent scientific developments in the utilization of nanotechnology-based drug delivery systems for treating oral malignancies that can lead to further improvements in clinical practice.

Methods

A comprehensive literature search was conducted on PubMed, Google Scholar, ScienceDirect, and other notable databases to identify recent peer-reviewed clinical trials, reviews, and research articles related to nanoplatforms and their applications in oral cancer treatment.

Results

Nanoplatforms offer a revolutionary strategy to overcome the challenges associated with conventional oral cancer treatments, such as poor drug solubility, non-specific targeting, and systemic toxicity. These nanoscale drug delivery systems encompass various formulations, including liposomes, polymeric nanoparticles, dendrimers, and hydrogels, which facilitate controlled release and targeted delivery of therapeutic agents to oral cancer sites. By exploiting the enhanced permeability and retention effect, Nanoplatforms accumulate preferentially in the tumor microenvironment, increasing drug concentration and minimizing damage to healthy tissues. Additionally, nanoplatforms can be engineered to carry multiple drugs or a combination of drugs and diagnostic agents, enabling personalized and precise treatment approaches.

Conclusion

The utilization of nanoplatforms in oral cancer treatment holds significant promise in revolutionizing therapeutic strategies. Despite the promising results in preclinical studies, further research is required to evaluate the safety, efficacy, and long-term effects of nanoformulations in clinical settings. If successfully translated into clinical practice, nanoplatform-based therapies have the potential to improve patient outcomes, reduce side effects, and pave the way for more personalized and effective oral cancer treatments.

Therapeutic efficacy of sorafenib and plant-derived phytochemicals in human colorectal cancer cells

BACKGROUND

The present study aimed to investigate the sequence-dependent anticancer effects of combined treatment with sorafenib (Sora), a Food and Drug Administration-approved multikinase inhibitor drug, and plant-derived phytochemicals (PPCs) on human colorectal cancer (CRC) cell growth, and proteins associated with the control of cell cycle and apoptosis.

METHODS

The cytotoxic effects of 14 PPCs on CRL1554 fibroblast cells were determined using an MTT assay. Moreover, the cytotoxicity of Sora, PPCs, and a combination of both on CRC cells were also investigated. Cell cycle analysis was performed using flow cytometry, and cell apoptosis was investigated using DNA fragmentation, Annexin V/propidium iodide double staining, and mitochondrial membrane potential analyses. The cell cycle- and apoptosis-associated protein expression levels were analysed using western blotting.

RESULTS

Based on their low levels of cytotoxicity in CRL1554 cells at ≤ 20%, curcumin, quercetin, kaempferol, and resveratrol were selected for use in subsequent experiments. The combined treatment of sora and PPCs caused levels of CRC cytotoxicity in a dose-, cell type-, and schedule-dependent manner. Moreover, the combined treatment of CRC cells arrested cell growth at the S and G2/M phases, induced apoptotic cell death, caused extensive mitochondrial membrane damage, and altered the expression of the cell cycle and apoptotic proteins.

CONCLUSIONS

Results of the present study highlighted a difference in the level of sora efficacy in CRC cells when combined with PPCs. Further in vivo and clinical studies using the combined treatment of sora and PPCs are required to determine their potential as a novel therapeutic strategy for CRCs.

Drug-drug interactions associated with FLT3 inhibitors for acute myeloblastic leukemia: current landscape

INTRODUCTION

FLT3 inhibitors (FLT3i) are drugs in which there is limited experience and not yet enough information on the mechanisms of absorption, transport, and elimination; but especially on the potential drug-drug interactions (DDIs). There are therefore risks in the management of FLT3i DDIs (i.e. sorafenib, ponatinib, crenolanib, midostaurin, quizartinib, and gilteritinib) and ignoring them can compromise therapeutic success in acute myeloid leukemia (AML) treatment, in complex patients and secondary pathologies.

AREAS COVERED

This review summarizes the DDIs of FLT3i with P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), organic anion transporting (OAT), organic cationic transporting (OCT), cytochrome P450 (CYP) subunits, and other minor metabolic/transport pathways. EMBASE, PubMed, the Cochrane Central Register and the Web of Science were searched. The last literature search was performed on the 14 February 2022.

EXPERT OPINION

FLT3i will be combined with other therapeutic agents (supportive care, doublet, or triplet therapy) and in different clinical settings, which means a greater chance of controlling and even eradicating the disease effectively, but also an increased risk to patients due to potential DDIs. Healthcare professionals should be aware of the potential interactions that may occur and be vigilant in monitoring those patients who are receiving any potentially interacting drug.

Hydrogels for localized chemotherapy of liver cancer: a possible strategy for improved and safe liver cancer treatment

The systemic drug has historically been preferred for the treatment of the majority of pathological conditions, particularly liver cancer. Indeed, this mode of treatment is associated with adverse reactions, toxicity, off-target accumulation, and rapid hepatic and renal clearance. Numerous efforts have been made to design systemic therapeutic carriers to improve retention while decreasing side effects and clearance. Following systemic medication, local administration of therapeutic agents allows for higher 'effective' doses with fewer side effects, kidney accumulation, and clearance. Hydrogels are highly biocompatible and can be used for both imaging and therapy. Hydrogel-based drug delivery approach has fewer side effects than traditional chemotherapy and can deliver drugs to tumors for a longer time. The chemical and physical flexibility of hydrogels can be used to achieve disease-induced in situ accumulation as well as subsequent drug release and hydrogel-programmed degradation. Moreover, they can act as a biocompatible depot for localized chemotherapy when stimuli-responsive carriers are administrated. Herein, we summarize the design strategies of various hydrogels used for localized chemotherapy of liver cancer and their delivery routes, as well as recent research on smart hydrogels.

Phase 1 study of sorafenib and irinotecan in pediatric patients with relapsed or refractory solid tumors

BACKGROUND

Sorafenib,an orally bioavailable, multitarget tyrosine kinase inhibitor, and irinotecan, a topoisomerase I inhibitor, have demonstrated activity in pediatric and adult malignancies. We evaluated the toxicity, pharmacokinetic (PK), and pharmacogenomic (PGX) profile of sorafenib with irinotecan in children with relapsed or refractory solid tumors and assessed the feasibility of incorporating patient-reported outcome (PRO) measures as an adjunct to traditional endpoints.

METHODS

Sorafenib, continuous oral twice daily dosing, was administered with irinotecan, orally, once daily days 1-5, repeated every 21 days (NCT01518413). Based on tolerability, escalation of sorafenib followed by escalation of irinotecan was planned. Three patients were initially enrolled at each dose level. Sorafenib and irinotecan PK analyses were performed during cycle 1. PRO measurements were collected during cycles 1 and 2.

RESULTS

Fifteen patients were evaluable. Two of three patients at dose level 2 experienced dose-limiting toxicity (DLT), grade 3 diarrhea, and grade 3 hyponatremia. Therefore, dose level 1 was expanded to 12 patients and two patients had DLT, grade 4 thrombocytopenia, grade 3 elevated lipase. Nine of 15 (60%) patients had a best response of stable disease with four patients receiving ≥6 cycles.

CONCLUSIONS

The recommended dose for pediatric patients was sorafenib 150 mg/m² /dose twice daily with irinotecan 70 mg/m² /dose daily × 5 days every 21 days. This oral outpatient regimen was well tolerated and resulted in prolonged disease stabilization. There were no significant alterations in the PK profile of either agent when administered in combination. Patients were willing and able to report their subjective experiences with this regimen.

Synthesis, potential antitumor activity, cell cycle analysis, and multitarget mechanisms of novel hydrazones incorporating a 4-methylsulfonylbenzene scaffold: a molecular docking study

Hydrazone is a bioactive pharmacophore that can be used to design antitumor agents. We synthesised a series of hydrazones (compounds 4–24) incorporating a 4-methylsulfonylbenzene scaffold and analysed their potential antitumor activity. Compounds 6, 9, 16, and 20 had the most antitumor activity with a positive cytotoxic effect (PCE) of 52/59, 27/59, 59/59, and 59/59, respectively, while compounds 5, 10, 14, 15, 18, and 19 had a moderate antitumor activity with a PCE of 11/59–14/59. Compound 20 was the most active and had a mean 50% cell growth inhibition (GI₅₀) of 0.26 µM. Compounds 9 and 20 showed the highest inhibitory activity against COX-2, with a half-maximal inhibitory concentration (IC₅₀) of 2.97 and 6.94 μM, respectively. Compounds 16 and 20 significantly inhibited EGFR (IC₅₀ = 0.2 and 0.19 μM, respectively) and HER2 (IC₅₀ = 0.13 and 0.07 μM, respectively). Molecular docking studies of derivatives 9, 16, and 20 into the binding sites of COX-2, EGFR, and HER2 were carried out to explore the interaction mode and the structural requirements for antitumor activity.

Design, synthesis, and analysis of antiproliferative and apoptosis-inducing activities of nitrile derivatives containing a benzofuran scaffold: EGFR inhibition assay and molecular modelling study

New cyanobenzofurans derivatives 2-12 were synthesised, and their antiproliferative activity was examined compared to doxorubicin and Afatinib (IC₅₀ = 4.17-8.87 and 5.5-11.2 µM, respectively). Compounds 2 and 8 exhibited broad-spectrum activity against HePG2 (IC₅₀ = 16.08-23.67 µM), HCT-116 (IC₅₀ = 8.81-13.85 µM), and MCF-7 (IC₅₀ = 8.36-17.28 µM) cell lines. Compounds 2, 3, 8, 10, and 11 were tested as EGFR-TK inhibitors to demonstrate their possible anti-tumour mechanism compared to gefitinib (IC₅₀ = 0.90 µM). Compounds 2, 3, 10, and 11 displayed significant EGFR TK inhibitory activity with IC₅₀ of 0.81-1.12 µM. Compounds 3 and 11 induced apoptosis at the Pre-G phase and cell cycle arrest at the G2/M phase. They also increased the level of caspase-3 by 5.7- and 7.3-fold, respectively. The molecular docking analysis of compounds 2, 3, 10, and 11 indicated that they could bind to the active site of EGFR TK.

The oncogene Mct-1 promotes progression of hepatocellular carcinoma via enhancement of Yap-mediated cell proliferation

Malignant T-cell-amplified sequence 1 (Mct-1) has been reported as an oncogene in multiple malignant diseases. However, the function of Mct-1 in hepatocellular carcinoma (HCC) and the molecular mechanisms underlying tumor progression have not been explored. In this study, Mct-1 expression levels in HCC tissues and cells were detected by quantitative real-time PCR and western blotting. Mct-1 shRNAs and overexpression vector were transfected into HCC cells to downregulate or upregulate Mct-1 expression. In vitro and in vivo assays were performed to investigate the function of Mct-1 in cell proliferation and apoptosis. RNA sequencing analysis (RNA-seq) was performed to explore differences in gene expression when silenced Mct-1 expression. Mct-1 was upregulated in HCC specimens and cell lines, and higher expression of Mct-1 was predictive of poor survival. Overexpression of Mct-1 was shown to promote cell proliferation and repress cell apoptosis both in vitro and in vivo. The results of RNA-seq indicated that knockdown of Mct-1 suppressed Yap expression, while the results of the luciferase assay also revealed that Mct-1 increases the activity of the Yap promoter. Restoration of Yap expression in Mct-1 knockdown cells partially recovered the promotion of cell proliferation and inhibition of apoptosis. Collectively, these results indicate that Mct-1 acts as a tumor promoter gene in HCC progression by up-regulating Yap expression and, thus, could serve a novel potential diagnostic and prognostic biomarker for HCC.

A 60% Edible Ethanolic Extract of Ulmus davidiana Inhibits Vascular Endothelial Growth Factor-Induced Angiogenesis

As abnormal angiogenesis is associated with exacerbation of various diseases, precise control over angiogenesis is imperative. Vascular endothelial growth factor (VEGF), the most well-known angiogenic factor, binds to VEGF receptor (VEGFR), activates various signaling pathways, and mediates angiogenesis. Therefore, blocking the VEGF-induced angiogenic response-related signaling pathways may alleviate various disease symptoms through inhibition of angiogenesis. Ulmus davidiana is a safe natural product that has been traditionally consumed, but its effects on endothelial cells (ECs) and the underlying mechanism of action are unclear. In the present study, we focused on the effect of a 60% edible ethanolic extract of U. davidiana (U60E) on angiogenesis. U60E inhibited the VEGF-mediated proliferation, tube formation, and migration ability of ECs. Mechanistically, U60E inhibited endothelial nitric oxide synthase activation and nitric oxide production by blocking the protein kinase B signaling pathway activated by VEGF and consequently inhibiting proliferation, tube formation, and migration of ECs. These results suggest that U60E could be a potential and safe therapeutic agent capable of suppressing proangiogenic diseases by inhibiting VEGF-induced angiogenesis.

Pilot study of the combination of sorafenib and fractionated irinotecan in pediatric relapse/refractory hepatic cancer (FINEX pilot study)

BACKGROUND

Preclinical observations suggested a synergistic effect of sorafenib (SFN) and irinotecan (CPT-11) in hepatoblastoma (HB). Thus, we conducted a feasibility study of fractionated CPT-11 combined with SFN to develop a new therapy against relapsed/refractory pediatric hepatic cancer (HC).

PROCEDURE

The study was originally designed as a phase I, standard 3+3 dose-finding study to evaluate dose-limiting toxicities (DLTs) for the regimen and the optimal CPT-11 dose in combination with SFN against relapsed/refractory pediatric HC, including HB and hepatocellular carcinoma (HCC). The enrolled patients received SFN at 200 mg/m² every 12 hours or 400 mg/m² every 24 hours daily combined with CPT-11 at 20 mg/m² /day on days 1 to 5 as an initial level 1 dose.

RESULTS

Six patients with HB (n = 4) or HCC (n = 2) were enrolled and treated with CPT-11 dose level 1. The median age at enrollment was 8.7 (6.2-16.3) years. All patients received platinum-containing chemotherapy, and five or two patients received CPT-11 or SFN before enrollment, respectively. Regimen toxicities were evaluable in all patients. One of six patients experienced a grade 4 transaminase levels increase, which was defined as a DLT per protocol. Grade 3/4 neutropenia and a grade 3 transaminase level increase occurred in three patients and one patient, respectively. All patients reported grade 1/2 toxicities such as anemia, skin toxicity, gastrointestinal symptoms, and hypoalbuminemia.

CONCLUSIONS

Although the study was terminated before determining the maximum-tolerated CPT-11 dose, SFN and CPT-11 at the level 1 dose were concluded to be tolerable in pediatric patients with HC.

Enhancing Anti-Tumor Activity of Sorafenib Mesoporous Silica Nanomatrix in Metastatic Breast Tumor and Hepatocellular Carcinoma via the Co-Administration with Flufenamic Acid

INTRODUCTION

Because tumor-associated inflammation is a hallmark of cancer treatment, in the present study, sorafenib mesoporous silica nanomatrix (MSNM@SFN) co-administrated with flufenamic acid (FFA, a non-steroidal anti-inflammatory drug (NSAID)) was investigated to enhance the anti-tumor activity of MSNM@SFN.

METHODS

Metastatic breast tumor 4T1/luc cells and hepatocellular carcinoma HepG2 cells were selected as cell models. The effects of FFA in vitro on cell migration, PGE2 secretion, and AKR1C1 and AKR1C3 levels in 4T1/luc and HepG2 cells were investigated. The in vivo anti-tumor activity of MSNM@SFN co-administrating with FFA (MSNM@SFN+FFA) was evaluated in a 4T1/luc metastatic tumor model, HepG2 tumor-bearing nude mice model, and HepG2 orthotopic tumor-bearing nude mice model, respectively.

RESULTS

The results indicated that FFA could markedly decrease cell migration, PGE2 secretion, and AKR1C1 and AKR1C3 levels in both 4T1/luc and HepG2 cells. The enhanced anti-tumor activity of MSNM@SFN+FFA compared with that of MSNM@SFN was confirmed in the 4T1/luc metastatic tumor model, HepG2 tumor-bearing nude mice model, and HepG2 orthotopic tumor-bearing nude mice model in vivo, respectively.

DISCUSSION

MSNM@SFN co-administrating with FFA (MSNM@SFN+FFA) developed in this study is an alternative strategy for improving the therapeutic efficacy of MSNM@SFN via co-administration with NSAIDs.

Simvastatin re-sensitizes hepatocellular carcinoma cells to sorafenib by inhibiting HIF-1α/PPAR-γ/PKM2-mediated glycolysis

BACKGROUND

Hepatocellular carcinoma (HCC) is a common primary malignant tumor which usually progresses to an advanced stage because of late diagnosis. Sorafenib (Sora) is a first line medicine for advanced stage HCC; however, it has been faced with enormous resistance. Simvastatin (Sim) is a cholesterol-lowering drug and has been reported to inhibit tumor growth. The present study aims to determine whether Sora and Sim co-treatment can improve Sora resistance in HCC.

METHODS

The HCC cell line LM3 and an established Sora-resistant LM3 cell line (LM3-SR) were used to study the relationship between Sora resistance and aerobic glycolysis. Cell proliferation, apoptosis and glycolysis levels were analyzed by western blotting, flow cytometry analysis and biomedical tests. A xenograft model was also used to examine the effect of Sim in vivo. Detailed mechanistic studies were also undertaken by the use of activators and inhibitors, and lentivirus transfections.

RESULTS

Our results demonstrated that the resistance to Sora was associated with enhanced aerobic glycolysis levels. Furthermore, LM3-SR cells were more sensitive to Sim than LM3 cells, suggesting that combined treatment with both Sora and Sim could enhance the sensitivity of LM3-SR cells to Sora. This finding may be due to the suppression of the HIF-1α/PPAR-γ/PKM2 axis.

CONCLUSIONS

Simvastatin can inhibit the HIF-1α/PPAR-γ/PKM2 axis, by suppressing PKM2-mediated glycolysis, resulting in decreased proliferation and increased apoptosis in HCC cells, and re-sensitizing HCC cells to Sora.

Hydrogel-Based Controlled Drug Delivery for Cancer Treatment: A Review

As an emerging drug carrier, hydrogels have been widely used for tumor drug delivery. A hydrogel drug carrier can cause less severe side effects than systemic chemotherapy and can achieve sustained delivery of a drug at tumor sites. In addition, hydrogels have excellent biocompatibility and biodegradability and lower toxicity than nanoparticle carriers. Smart hydrogels can respond to stimuli in the environment (e.g., heat, pH, light, and ultrasound), enabling in situ gelation and controlled drug release, which greatly enhance the convenience and efficiency of drug delivery. Here, we summarize the different sizes of hydrogels used for cancer treatment and their related delivery routes, discuss the design strategies for stimuli-responsive hydrogels, and review the research concerning smart hydrogels reported in the past few years.

Isomorphous Crystals Formed by the Similar Supramolecular Motifs in Sorafenib Hydrochloride and Regorafenib Hydrochloride Salts

Sorafenib and regorafenib (or fluoro-sorafenib) are multikinase inhibitors active in the treatment of various human cancers, but their solubilities are very poor. To improve their solubilities, in this study, sorafenib hydrochloride (Sor·HCl, I) and regorafenib hydrochloride (Reg·HCl, II) have been prepared and their crystal structures were characterized. Their solubility properties in water were evaluated. Intriguingly, they are isomorphous crystal structures with the same space group and the similar unit cell dimensions, which were caused by the similar supramolecular patterns resulted by the formation of N–H···Cl− hydrogen bond instead of hydrogen bond between the protonated pyridinium cation and counterion. Moreover, the solubility properties displayed identical profiles. It may be concluded that a similar crystal structure leads to a comparable solubility profile.

Not the comfy chair! Cancer drugs that act against multiple active sites

Introduction: Discoveries of novel signal transduction pathways in the 1990s stimulated drug companies to develop small molecule tyrosine kinase and serine / threonine kinase inhibitors which were based on catalytic site inhibition. All kinases bind ATP and catalyze phosphate transfer and, therefore, inhibitors that block ATP binding and its metabolism would be predicted to have a known on-target specificity but were also likely to have many unknown or unrecognized targets due to similarities in all ATP binding pockets. This on-target off-target biology of kinase inhibitors, which exhibit a "signal" in the clinic, means that therapeutically valuable agents are acting through unknown biological processes to mediate their anti-tumor effects.Areas covered: This perspective discusses drug therapies whose actions cannot be explained by their actions on the original targeted kinase; it concludes with a methodology to screen for changes in cell signaling via in-cell western immunoblotting.Expert opinion: Most malignancies do not depend on survival signaling from one specific mutated proto-oncogene, especially for previously treated malignancies where multiple clonal variants of the primary tumor have evolved. Hence, the concept of a highly "personalized medicine" approach fails because it is unlikely that a specific therapy will kill all clonal variants of the tumor.

A novel reporter construct for screening small molecule inhibitors that specifically target self-renewing cancer cells

Cancer stem cells (CSCs) are a subset of cancer cells, which possess self-renewal ability, and lead to tumor progression, metastasis, and resistance to therapy. Live detection and isolation of CSCs are important to understand the biology of CSCs as well as to screen drugs that target them. Even though CSCs are detected using surface markers, there is a lot of inconsistencies for that in a given cancer type. At the same time, self-renewal markers like ALDH1A1, OCT4A and SOX2, which are intracellular molecules, are reliable markers for CSCs in different cancers. In the present study, we generated a reporter construct for self-renewing CSCs, based on ALDH1A1 expression. Oral cancer cells harboring ALDH1A1-DsRed2 were used to screen inhibitors that target CSCs. Our results showed that Comb1, a cocktail of inhibitors for EGF and TGF-β pathways and their intermediates, effectively reduced the DsRed2 population to 34%. Our immunohistochemical analysis on primary oral cancer corroborated the importance of EGF and TGF-β pathways in sustaining CSCs. Since these two pathways are also critical for the self-renewal and differentiation of normal stem cells, Comb1 might abolish them as well. On analysis of the effect of Comb1 on normal murine bone marrow cells, there was no significant change in the stem cell self-renewal and differentiation potential in the treated group compared to untreated cells. To conclude, we claim that ALDH1A1-DsRed2 is a useful tool to detect CSCs, and Comb1 is effective in targeting CSCs without affecting normal stem cells.

Functional Biological Activity of Sorafenib as a Tumor-Treating Field Sensitizer for Glioblastoma Therapy

Glioblastoma, the most common primary brain tumor in adults, is an incurable malignancy with poor short-term survival and is typically treated with radiotherapy along with temozolomide. While the development of tumor-treating fields (TTFields), electric fields with alternating low and intermediate intensity has facilitated glioblastoma treatment, clinical outcomes of TTFields are reportedly inconsistent. However, combinatorial administration of chemotherapy with TTFields has proven effective for glioblastoma patients. Sorafenib, an anti-proliferative and apoptogenic agent, is used as first-line treatment for glioblastoma. This study aimed to investigate the effect of sorafenib on TTFields-induced anti-tumor and anti-angiogenesis responses in glioblastoma cells in vitro and in vivo. Sorafenib sensitized glioblastoma cells to TTFields, as evident from significantly decreased post-TTFields cell viability (p < 0.05), and combinatorial treatment with sorafenib and TTFields accelerated apoptosis via reactive oxygen species (ROS) generation, as evident from Poly (ADP-ribose) polymerase (PARP) cleavage. Furthermore, use of sorafenib plus TTFields increased autophagy, as evident from LC3 upregulation and autophagic vacuole formation. Cell cycle markers accumulated, and cells underwent a G2/M arrest, with an increased G0/G1 cell ratio. In addition, the combinatorial treatment significantly inhibited tumor cell motility and invasiveness, and angiogenesis. Our results suggest that combination therapy with sorafenib and TTFields is slightly better than each individual therapy and could potentially be used to treat glioblastoma in clinic, which requires further studies.

Management of pediatric hepatocellular carcinoma: A multimodal approach

HCC is rare in the pediatric population, but is the second most common liver malignancy in children. Survival rates for primary unresectable HCC have been dismal. The objective of this study was to describe our experience with a multimodal approach for the management of unresectable HCC in two adolescent patients and to review the literature. Both patients are currently alive with no recurrence at 51 and 29 months post-transplant. Multimodality treatment involving chemotherapy with doxorubicin, cisplatin, and sorafenib; TACE; timely liver transplantation; and post-transplant therapy with sorafenib and mTOR inhibitors may help improve outcomes and prolong survival in pediatric patients with unresectable HCC.

A formulated red ginseng extract inhibits autophagic flux and sensitizes to doxorubicin-induced cell death

Background

Ginseng is believed to have antitumor activity. Autophagy is largely a prosurvival cellular process that is activated in response to cellular stressors, including cytotoxic chemotherapy; therefore, agents that inhibit autophagy can be used as chemosensitizers in cancer treatment. We examined the ability of Korean Red Ginseng extract (RGE) to prevent autophagic flux and to make hepatocellular carcinoma (HCC) cells become more sensitive to doxorubicin.

Methods

The cytotoxic effects of total RGE or its saponin fraction (RGS) on HCC cells were examined by the lactate dehydrogenase assay in a dose- or time-dependent manner. The effect of RGE or RGS on autophagy was measured by analyzing microtubule-associated protein 1A/1B-light chain (LC)3-II expression and LC3 puncta formation in HCC cells. Late-stage autophagy suppression was tested using tandem-labeled green fluorescent protein (GFP)-monomeric red fluorescent protein (mRFP)-LC3.

Results

RGE markedly increased the amount of LC3-II, but green and red puncta in tandem-labeled GFP-mRFP-LC3 remained colocalized over time, indicating that RGE inhibited autophagy at a late stage. Suppression of autophagy through knockdown of key ATG genes increased doxorubicin-induced cell death, suggesting that autophagy induced by doxorubicin has a protective function in HCC. Finally, RGE and RGS markedly sensitized HCC cells, (but not normal liver cells), to doxorubicin-induced cell death.

Conclusion

Our data suggest that inhibition of late-stage autophagic flux by RGE is important for its potentiation of doxorubicin-induced cancer cell death. Therapy combining RGE with doxorubicin could serve as an effective strategy in the treatment of HCC.

Transcatheter hepatic arterial chemoembolization and sorafenib for hepatocellular carcinoma: a meta-analysis of randomized, double-blind controlled trials

We performed a meta-analysis of transcatheter hepatic arterial chemoembolization (TACE) combined with sorafenib for hepatocellular carcinoma (HCC), which included 4 double-blind, randomized controlled trials (RCTs) that investigated the effects of TACE combined with sorafenib (experimental groups) on time to disease progression (TTP), overall survival (OS), and various sorafenib-related adverse events, compared to those in the placebo (control) groups. A total of 877 HCC cases from 14 countries, including China and the USA, were included in our meta-analysis. The TTP increased significantly in the experimental groups (hazard ration [HR]: 0.82; 95% CI: 0.69–0.97; p = 0.02), but OS did not improve significantly (HR: 0.97; 95% CI: 0.72–1.29; p = 0.82), compared with the control groups. The risks of hand and foot skin reactions (HFSR), rash, fatigue, and diarrhea were significantly greater in the experimental groups (p < 0.05 for all), compared to those in the control groups, whereas the risk of nausea was statistically similar (p > 0.05). Among these, the risk of HFSR was highest (risk ratio [RR]: 5.93; 95% CI: 2.00–17.53; p = 0.001), and a subgroup analysis of studies that lacked significant heterogeneity in the HFSR data showed a higher risk of HFSR (RR: 10.96; 95% CI: 5.54–21.69; p < 0.05). In conclusion, although TACE plus sorafenib increases TTP, it does not improve OS. Therefore, the risk of the adverse events of TACE plus sorafenib should be considered as a potential therapeutic limitation.

Changes in tumor oxygen state after sorafenib therapy evaluated by 18F-fluoromisonidazole hypoxia imaging of renal cell carcinoma xenografts

A mechanistic dissociation exists between tumor starvation and vascular normalization after antiangiogenic therapy. Thus, improved understanding of tumor responses (tumor starvation or vascular normalization) is important for optimizing treatment strategies. ¹⁸F-fluoromisonidazole (¹⁸F-FMISO) is widely used for imaging tumor hypoxia. To clarify the tumor response to the antiangiogenic drug sorafenib, the present study evaluated the changes in the tumor oxygen state using ¹⁸F-FMISO in mice bearing a renal cell carcinoma xenograft (A498). Mice bearing A498 xenografts were assigned to the control and three sorafenib-treatment groups and administered sorafenib (0, 10, 20 or 40 mg/kg/day, per os) once daily for 3 days. Following one day after the final administration, the mice were injected with ¹⁸F-FMISO and pimonidazole (a hypoxia marker). ¹⁸F-FMISO accumulation in the tumor was determined by autoradiography. Immunohistochemistry of pimonidazole and cluster of differentiation (CD)31 (a vascular marker) was also performed. ¹⁸F-FMISO accumulation levels in the tumor significantly increased by 4.3-, 8.4- and 8.6-fold compared with in the control group following 10, 20 and 40 mg/kg sorafenib treatments, respectively [0.07±0.04, 0.32±0.11, 0.62±0.15 and 0.63±0.23 (%ID/m²) × kg for the control, and 10, 20 and 40 mg treatments, respectively; all P<0.0083 vs. the control]. The number of pimonidazole-positive cells also significantly increased by 6.8-, 12.3- and 20.2-fold compared with in the control group following 10, 20 and 40 mg/kg sorafenib treatments, respectively (0.78±0.79, 5.36±2.29, 9.66±1.58 and 15.85±4.59% pimonidazole-positive cells; all P<0.0083 vs. the control). The number of microvessels in tumors markedly decreased to 33.5, 17.6, and 14.0% of the control following 10, 20 and 40 mg/kg sorafenib treatments, respectively (17.1±2.5, 5.7±1.0, 3.0±1.0 and 2.4±0.3 vessels/mm²; P<0.0083 vs. the control). The ¹⁸F-FMISO expression level in the tumor increased sorafenib-dose-dependently, which is consistent with the increase in the number of pimonidazole-positive cells and decrease in the number of microvessels. These findings indicated that the present sorafenib treatment protocol induces 'tumor hypoxia/starvation' in the renal cell carcinoma xenograft (A498) due to its antiangiogenic properties.

New knowledge of the mechanisms of sorafenib resistance in liver cancer

Sorafenib is an oral multikinase inhibitor that suppresses tumor cell proliferation and angiogenesis and promotes tumor cell apoptosis. It was approved by the FDA for the treatment of advanced renal cell carcinoma in 2006, and as a unique target drug for advanced hepatocellular carcinoma (HCC) in 2007. Sorafenib can significantly extend the median survival time of patients but only by 3-5 months. Moreover, it is associated with serious adverse side effects, and drug resistance often develops. Therefore, it is of great importance to explore the mechanisms underlying sorafenib resistance and to develop individualized therapeutic strategies for coping with these problems. Recent studies have revealed that in addition to the primary resistance, several mechanisms are underlying the acquired resistance to sorafenib, such as crosstalk involving PI3K/Akt and JAK-STAT pathways, the activation of hypoxia-inducible pathways, and epithelial-mesenchymal transition. Here, we briefly describe the function of sorafenib, its clinical application, and the molecular mechanisms for drug resistance, especially for HCC patients.

Pediatric hepatocellular carcinoma: challenges and solutions

Hepatocellular carcinoma (HCC) is a very rare entity in children, making it nearly impossible to orchestrate Phase II/III studies even as multinational cooperative trials. In contrast to adults, nearly 50% of the children have a response (α-fetoprotein decline and/or tumor shrinkage) to chemotherapeutic agents such as cisplatin and doxorubicin (PLADO), demonstrating that HCC in childhood can be chemotherapy sensitive. As a result, the main treatment options in pediatric HCC focus on systemic drug therapies and resection as the central therapy. In nonmetastatic patients with complete resection upfront, the 5-year event-free survival and overall survival has reached 80%–90%. In almost all reported studies, children received adjuvant chemotherapy (mostly PLADO), but it has never been proven that postoperative chemotherapy is superior to observation. No data are available for the effects of sorafenib. The 3-year survival is <20% in children with unresectable HCC independent of the chemotherapy given preoperatively. Currently, PLADO in combination with sorafenib is recommended with the goal of achieving operability status. Alternatively, data are promising for the combination of sorafenib with gemcitabine and oxaliplatin. For children with nonresectable and nonmetastastic liver tumors, it has been shown that the Milan criteria regarding liver transplantation are not applicable – individual decisions have to be made. Transarterial chemoembolization could be offered to patients with chemotherapy-resistant liver tumors for palliative care or potentially to achieve surgical resectability, and therefore cure. Information about the feasibility or effects of new agents or approaches as discussed in adult HCC patients is not available for childhood HCC. Research has to be done for characterizing the molecular and genomic mechanisms of pediatric HCC to support the development of novel therapeutic approaches and the implementation of personalized medicine.

Synergistic Combination for Chemoprevention of Hepatocellular Carcinoma: An In Silico and In Vitro Approach

Combination therapy is one of the best methods to manage the fatality rate in hepatocellular carcinoma (HCC). This study aimed to formulate a synergistic combination of synthetic and herbal compounds for the treatment of HCC as well as to elucidate a possible signalling mechanism. MTT and enzymatic assay were performed to determine the synergistic effect of drug combination (sorafenib, vitamin K1 and trans-chalcone) on HepG2 cell lines after intoxication with H₂ O₂ . Protein-protein interaction and docking studies were performed using Pathwaylinker2.0 and Schrödinger's software application to find out the mechanism of action and major targets for drug combination. The overall in vitro result showed that combination of trans-chalcone, vitamin K1 and sorafenib (10, 5 and 5 μM concentration, respectively) enhanced the resistance against oxidative stress generated by H₂ O₂ . The interaction studies helped in identification of few targets for docking of ligands (trans-chalcone, vitamin K1 and sorafenib). The study reports the synergistic effects of the formulation that can protect the cells from oxidative stress and restore normal levels of cellular enzymes in HepG2 cell line. We were able to determine the mechanism of action of herbal and synthetic formulation through in silico studies. Finally, docking studies confirmed potential targets for inhibition of hepatocarcinogenesis.

New tricks for old dogs: countering antibiotic resistance in tuberculosis with host-directed therapeutics

Despite the availability of Mycobacterium tuberculosis (Mtb) drugs for over 50 years, tuberculosis (TB) remains at pandemic levels. New drugs are urgently needed for resistant strains, shortening duration of treatment, and targeting different stages of the disease, especially for treatment during human immunodeficiency virus co-infection. One solution to the conundrum that antibiotics kill the bacillus yet select for resistance is to target the host rather than the pathogen. Here, we discuss recent progress in so-called 'host-directed therapeutics' (HDTs), focusing on two general mechanistic strategies: (i) HDTs that disrupt Mtb pathogenesis in macrophages and (ii) immunomodulatory HDTs that facilitate protective immune responses that kill Mtb or reduce deleterious responses that exacerbate disease. HDTs hold significant promise as adjunctive therapies in that they are less likely to engender resistance, will likely have efficacy against antibiotic-resistant strains, and may have activity against non-replicating Mtb. However, TB is a complex and variegated disease, and human populations exhibit significant diversity in their immune responses to it, which presents a complicated landscape for HDTs to navigate. Nevertheless, we suggest that a detailed mechanistic understanding of drug action, together with careful selection of disease stage targets and dosing strategies may overcome such limitations and allow the development of HDTs as effective adjunctive treatment options for TB.

Metabolism-related pharmacokinetic drug-drug interactions with tyrosine kinase inhibitors: current understanding, challenges and recommendations

Drug-drug interactions (DDIs) occur when a patient's response to the drug is modified by administration or co-exposure to another drug. The main cytochrome P450 (CYP) enzyme, CYP3A4, is implicated in the metabolism of almost all of the tyrosine kinase inhibitors (TKIs). Therefore, there is a substantial potential for interaction between TKIs and other drugs that modulate the activity of this metabolic pathway. Cancer patients are susceptible to DDIs as they receive many medications, either for supportive care or for treatment of toxicity. Differences in DDI outcomes are generally negligible because of the wide therapeutic window of common drugs. However for anticancer agents, serious clinical consequences may occur from small changes in drug metabolism and pharmacokinetics. Therefore, the objective of this review is to highlight the current understanding of DDIs among TKIs, with a focus on metabolism, as well as to identify challenges in the prediction of DDIs and provide recommendations.

NMR-Based Metabolic Profiling Reveals Neurochemical Alterations in the Brain of Rats Treated with Sorafenib

Sorafenib, an active multi-kinase inhibitor, has been widely used as a chemotherapy drug to treat advanced clear-cell renal cell carcinoma patients. In spite of the relative safety, sorafenib has been shown to exert a negative impact on cognitive functioning in cancer patients, specifically on learning and memory; however, the underlying mechanism remains unclear. In this study, an NMR-based metabolomics approach was applied to investigate the neurochemical effects of sorafenib in rats. Male rats were once daily administrated with 120 mg/kg sorafenib by gavage for 3, 7, and 28 days, respectively. NMR-based metabolomics coupled with histopathology examinations for hippocampus, prefrontal cortex (PFC), and striatum were performed. The (1)H NMR spectra data were analyzed by using multivariate pattern recognition techniques to show the time-dependent biochemical variations induced by sorafenib. Excellent separation was obtained and distinguishing metabolites were observed between sorafenib-treated and control rats. A total of 36 differential metabolites in hippocampus of rats treated with sorafenib were identified, some of which were significantly changed. Furthermore, these modified metabolites mainly reflected the disturbances in neurotransmitters, energy metabolism, membrane, and amino acids. However, only a few metabolites in PFC and striatum were altered by sorafenib. Additionally, no apparent histological changes in these three brain regions were observed in sorafenib-treated rats. Together, our findings demonstrate the disturbed metabonomics pathways, especially, in hippocampus, which may underlie the sorafenib-induced cognitive deficits in patients. This work also shows the advantage of NMR-based metabolomics over traditional approach on the study of biochemical effects of drugs.

20(S)-Ginsenoside Rg3 is a novel inhibitor of autophagy and sensitizes hepatocellular carcinoma to doxorubicin

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. High mortality from HCC is mainly due to widespread prevalence and the lack of effective treatment, since systemic chemotherapy is ineffective, while the targeted agent Sorafenib extends median survival only briefly. The steroidal saponin 20(S)-ginsenoside Rg₃ from Panax ginseng C.A. Meyer is proposed to chemosensitize to various therapeutic drugs through an unknown mechanism. Since autophagy often serves as cell survival mechanism in cancer cells exposed to chemotherapeutic agents, we examined the ability of Rg₃ to inhibit autophagy and chemosensitize HCC cell lines to doxorubicin in vitro. We show that Rg₃ inhibits late stage autophagy, possibly through changes in gene expression. Doxorubicin-induced autophagy plays a protective role in HCC cells, and therefore Rg₃ treatment synergizes with doxorubicin to kill HCC cell lines, but the combination is relatively nontoxic in normal liver cells. In addition, Rg₃ was well-tolerated in mice and synergized with doxorubicin to inhibit tumor growth in HCC xenografts in vivo. Since novel in vivo inhibitors of autophagy are desirable for clinical use, we propose that Rg3 is such a compound, and that combination therapy with classical chemotherapeutic drugs may represent an effective therapeutic strategy for HCC treatment.

Sorafenib: a brief review with emphasis on its possible role in breast cancer

SUMMARY 

The treatment of metastatic breast cancer is palliative and usually requires hormone treatment, and/or chemotherapy and trastuzumab for HER2-positive disease. Randomized studies only demonstrate marginal survival benefit with combination chemotherapy, as opposed to sequential single agents or nontaxane versus taxane-containing regimens. Metastatic breast cancer remains an unmet medical need. Sorafenib is an oral multikinase inhibitor that exhibits antiangiogenic activity by targeting numerous proangiogenic pathways. Sorafenib has marketing authorization for the treatment of patients with advanced renal cell, hepatocellular and thyroid carcinomas. Recent studies have explored the usage of sorafenib as a single agent and in combination with chemotherapy. An overview of sorafenib is presented in this article with the current data and potential future usage in patients with metastatic breast cancer.

Binding interaction between sorafenib and calf thymus DNA: spectroscopic methodology, viscosity measurement and molecular docking

The binding interaction of sorafenib with calf thymus DNA (ct-DNA) was studied using UV-vis absorption spectroscopy, fluorescence emission spectroscopy, circular dichroism (CD), viscosity measurement and molecular docking methods. The experimental results revealed that there was obvious binding interaction between sorafenib and ct-DNA. The binding constant (Kb) of sorafenib with ct-DNA was 5.6×10(3) M(-1) at 298 K. The enthalpy and entropy changes (ΔH(0) and ΔS(0)) in the binding process of sorafenib with ct-DNA were -27.66 KJ mol(-1) and -21.02 J mol(-1) K(-1), respectively, indicating that the main binding interaction forces were van der Waals force and hydrogen bonding. The docking results suggested that sorafenib preferred to bind on the minor groove of A-T rich DNA and the binding site of sorafenib was 4 base pairs long. The conformation change of sorafenib in the sorafenib-DNA complex was obviously observed and the change was close relation with the structure of DNA, implying that the flexibility of sorafenib molecule played an important role in the formation of the stable sorafenib-ct-DNA complex.

Novel antiangiogenic drugs for the management of breast cancer: new approaches for an old issue?

Since angiogenesis plays an important role in cancer growth, infiltration and metastasis, many agents targeting this pathway have been developed over the last decade. Antiangiogenic drugs interfere with this process and may inhibit neoplastic growth or induce tumor dormancy by blocking the expanding network of newly formed capillaries. Despite the initial promise, targeting angiogenesis in breast cancer has not reached major breakthroughs. Nevertheless, the immunologic role of VEGF deserves to be further explored. We aim to describe the biological mechanisms which underlie the role of angiogenesis in breast cancer carcinogenesis, to depict its contribution to the metastatic process and to review the most important clinical trials testing angiogenic inhibitors in breast cancer, including monoclonal antibodies and novel small molecules.

Investigation of antitumor effects of sorafenib and lapatinib alone and in combination on MCF-7 breast cancer cells

BACKGROUND

Breast cancer evolution and tumor progression are controlled by complex interactions between steroid receptors and growth factor receptor signaling. Aberrant growth factor receptor signaling can augment or suppress estrogen receptor function in hormone-dependent breast cancer cells. Thus, we aimed to investigate antitumor effects of sorafenib and lapatinib alone and in combination on MCF-7 breast cancer cells.

MATERIALS AND METHODS

Cytotoxicity of the sorafenib and lapatinib was tested in MCF-7 cells by XTT assays. 50, 25, 12.5 and 6.25μM concentrations of sorafenib and 200, 100, 50 and 25μM concentrations of lapatinib were administered alone and in combination. Results were evaluated as absorbance at 450nM and IC50 values are calculated according to the absorbance data

RESULTS

Both sorafenib and lapatinib showed concentration dependent cytotoxic effects on MCF-7 cells. Sorafenib exerted cytotoxic effects with an IC50 value of 32.0μM; in contrast with lapatinib the IC50 was 136.6μM. When sorafenib and lapatinib combined, lapatinib increased cytotoxic effects of sorafenib at its ineffective concentrations. Also at the concentrations where both drugs had cytotoxic effects, combination show strong anticancer effects and killed approximately 70 percent of breast cancer cells.

CONCLUSIONS

Combinations of tyrosine kinase inhibitors and cytotoxic agents or molecular targeted therapy has been successful for many types of cancer. The present study shows that both sorafenib and lapatinib alone are effective in the treatment of breast cancer. Also a combination of these two agents may be a promising therapeutic option in treatment of breast cancer.

Binding interaction of sorafenib with bovine serum albumin: Spectroscopic methodologies and molecular docking

The binding interaction of sorafenib with bovine serum albumin (BSA) was studied using fluorescence, circular dichrosim (CD) and molecular docking methods. The results revealed that there was a static quenching of BSA induced by sorafenib due to the formation of sorafenib-BSA complex. The binding constant and number of binding site of sorafenib with BSA under simulated physiological condition (pH=7.4) were 6.8×10(4) M(-1) and 1 at 310 K, respectively. Base on the sign and magnitude of the enthalpy and entropy changes (ΔH(0)=-72.2 kJ mol(-1) and ΔS(0)=-140.4J mol(-1) K(-1)) and the results of molecular docking, it could be suggested that the binding process of sorafenib and BSA was spontaneous and the main interaction forces of sorafenib with BSA were van der Waals force and hydrogen bonding interaction. From the results of site marker competitive experiments and molecular docking, it could be deduced that sorafenib was inserted into the subdomain IIA (site I) of BSA and leads to a slight change of the conformation of BSA. And, the significant change of conformation of sorafenib occurred in the binding process with BSA to increase the stability of the sorafenib-BSA system, implying that the flexibility of sorafenib played an important role in the binding process.

The mechanisms responsible for the radiosensitizing effects of sorafenib on colon cancer cells

Colorectal cancer is one of the most common malignancies in the world, and is generally treated more effectively by chemoradiotherapy rather than radiotherapy or chemotherapy alone. Targeted radiosensitizers are often used in order to enhance the radiosensitivity of tumor cells. The aim of the present study was to identify the mechanism of radiosensitization by sorafenib in colorectal cancer. Three human colorectal adenocarcinoma cell lines (HCT116, HT29 and SW480) were treated with sorafenib alone or radiation followed by sorafenib. In vitro tests were performed using colony forming assays, FACS analysis, immunohistochemistry, tumor cell motility assays, invasion assays and endothelial tube formation assays. Sorafenib enhanced the anti-proliferative effects of radiation, reducing colony formation, increasing G2/M arrest and enhancing radiation-induced apoptosis by reactive oxygen species. Sorafenib also inhibited the repair of radiation-induced DNA damage by blocking the activation of DNA-dependent protein kinase. Combination treatment significantly inhibited tumor cell migration, tumor cell invasion and vascular endothelial growth factor-mediated angiogenesis in vitro. Taken together, our results provide a scientific rationale for the use of sorafenib with radiotherapy in colon cancer and suggest a clinical utility for this approach.

Multiobjective optimization on antiplatelet effects of three components combination by quantitative composition-activity relationship modeling and weighted-sum method

Multicomponent therapeutic has become an increasingly favored strategy for treating complex diseases in recent years. In this study, a multiple objective optimization approach was proposed to design the optimal combination of three components for antiplatelet activity. The platelet aggregation assays induced by three different ways, adenosine diphosphate, arachidonic acid, and collagen, were applied to evaluate the in vitro antiplatelet activities of three active components derived from a traditional Chinese medicine. After analyzing this dataset by quantitative composition-activity relationship modeling, a weighted-sum optimization method was adopted to calculate the optimal ratio between three components for antiplatelet effects. Further experiments validated our method and showed that better antiplatelet activity was exerted by the optimized combination than the individual component or other combinations. Our findings suggested that the proposed multiobjective optimization approach is a novel method for multicomponent drug design.

Systemic therapies in hepatocellular carcinoma: present and future

Hepatocellular carcinoma (HCC) is now the third leading cause of cancer deathsworldwide and is generally presented at an advanced stage, limiting patients' quality of life. The conventional cytotoxic systemic therapy has proved to be ineffective in HCC, since its induction several decades ago. Today it is possible to use our knowledge of molecular hepatocarcinogenesis to provide a targeted therapy. Sorafenib has demonstrated large improvements in overall survival in HCC. This review describes the molecular mechanisms and potential therapeutic targets, focusing on sorafenib, sunitinib, tivantinib, antiangiogenic agents, and current and future immunotherapies. Thus, it will be necessary in the future to classify HCCs into subgroups according to their genomic and proteomic profiling. The identification of key molecules/receptors/signaling pathways and the assessment of their relevance as potential targets will be the main future challenge potentially influencing response to therapy. Defining molecular targeted agents that are effective for a specific HCC subgroup will hopefully lead to personalized therapy.

Reversal of acquired drug resistance in FLT3-mutated acute myeloid leukemia cells via distinct drug combination strategies

PURPOSE

FMS-like tyrosine kinase-3 (FLT3) internal tandem duplication (FLT3-ITD) mutations are common in patients with acute myeloid leukemia (AML). These patients regularly develop resistance to FLT3 inhibitors suggesting that targeted combination drug strategies are needed to enhance AML therapy efficacy.

EXPERIMENTAL DESIGN

Acquired point mutations of FLT3-ITD gene were screened using cDNA-based sequencing approach in vitro sorafenib-resistant cells, which were developed by long-term exposure of Ba/F3-ITD to increasing doses of sorafenib, and in FLT3-ITD mutated AML patients, who developed relapse following sorafenib therapy. Drug effects (e.g., proliferation inhibition, apoptosis induction, and changes in signal transduction protein expression) were assessed in AML cells harboring the point mutations in vitro and in FLT3-ITD-mutated AML patient samples.

RESULTS

We identified several acquired point mutations in the tyrosine kinase domains (TKD) of the FLT3 gene in sorafenib-resistant murine leukemia cell line carrying human FLT3-ITD mutations, which were also detected in two of four sorafenib-resistant patient samples. Engineering these point mutations into Ba/F3-ITD cells generated sublines that demonstrated varying degrees of sorafenib [a type II tyrosine kinase inhibitor (TKI)] resistance. A similar pattern of resistance could be observed by exposing these sublines to the other type II TKIs AC220 and MLN518. However, these sublines retained sensitivity to the type I TKIs PKC412 or crenolanib. The combination of crenolanib with sorafenib demonstrated marked cytotoxic effects in all of the sorafenib-resistant sublines.

CONCLUSIONS

These combination strategies could be clinically important in reversing acquired resistance to FLT3 inhibition in AML.